Militants had previously claimed responsibility for the attack, confirmed today by officials, which occurred in the relatively stable region of Badakhshan on Wednesday.

Attacks with high numbers of casualties for the state’s military are becoming increasingly common as insurgents step up their campaign against government forces.

Afghan officers now lead around 90 per cent of all operations across the country, with foreign combat forces set to withdraw completely from Afghanistan in 2014.

But with questions being asked about the speed and timing of the withdrawal of international support, a rare incident like this in Badakhshan highlights the nation’s struggle to keep the Taliban at bay.

“The acting interior minister is deeply saddened about the killing of 18 policemen and wounding of 13 others in a terrorist attack in Warduj district of Badakhshan,” a statement from the ministry said.

“A group of Afghan police forces on their return from a clean-up operation on the outskirts of Warduj district faced an enemy ambush and it resulted in the killing of brave Afghan policemen.”

The statement added that 47 insurgents were killed in the same area during a police operation earlier in the week.

The Badakhshan region, nestled in the Hindu Kush and Pamir mountain ranges and bordering China, is one of the most remote in the country.